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DIY: Do It Yourself Post here to share or improve your wrench turning skills! All BMW E46 DIY tips, tales, and projects discussed inside. Learn to work on your car and know the right BMW parts you will need!

Mine was a bad relay... it's behind your glove box. I checked and checked over everything constantly and all was working, after clearing the codes over and over at Advance Auto I was able to diagnose it thru trial and error. Sometimes the system would be fine, other times the light would trigger, all times I would hear the air pump kick on. Ultimately it was the relay which occasionally delayed the start of the system which triggered the light. It's a $13 OEM part. After I took my old one out I took it apart by removing the cover and sure enough the contact point inside was charred.

To answer you question though, theres just two bolts/nuts that hold it on, but removing it my require a new gasket. Try using a U-joint. Should be straight forward though. Take the hose off and feel in there for blockage with the motor OFF. Then on a cold morning when it kicks open at first start (verify it's doing this), shoot a little throttle body cleaner or seafoam in it then hook the pump hose back up to blow it thru the ports. I did that but it didn't fix anything.

Mine was a bad relay... it's behind your glove box. I checked and checked over everything constantly and all was working, after clearing the codes over and over at Advance Auto I was able to diagnose it thru trial and error. Sometimes the system would be fine, other times the light would trigger, all times I would hear the air pump kick on. Ultimately it was the relay which occasionally delayed the start of the system which triggered the light. It's a $13 OEM part. After I took my old one out I took it apart by removing the cover and sure enough the contact point inside was charred.

To answer you question though, theres just two bolts/nuts that hold it on, but removing it my require a new gasket. Try using a U-joint. Should be straight forward though. Take the hose off and feel in there for blockage with the motor OFF. Then on a cold morning when it kicks open at first start (verify it's doing this), shoot a little throttle body cleaner or seafoam in it then hook the pump hose back up to blow it thru the ports. I did that but it didn't fix anything.

Ok thanks guys, I will check the relay...I think I saw a post showing where it's located somewhere on the forum. Will keep you posted. Thanks again.

Instead of removing the valve, use the blowing power of the Secondary air pump to blow Seafoam solvent through the valve and into the exhaust ports.

To clear this carbon, pour Seafoam into the hose from secondary air pump to the valve and engine port before the cold engine is started in the morning.

The hose will hold just over an ounce of Seafoam. Reconnect the hose and run the car 5 seconds so the air pump blows the Seafoam into the exhaust port. Repeat this fill and restart 3 more times only running the engine 5 seconds so the secondary air pump runs for the 3 fills.

Then let the engine sit 15 minutes and warm up the car. There will be significant amounts of Seafoam carbon burnoff in the form of white smoke. The carbon burnoff will clean exhaust areas in the path to the O2 sensors that measure secondary air flow.

Since doing this using a couple of cans over a few months, the CELs have gone away and the engine feels smoother.

Does running SeaFoam do any harm to the O2 sensors?
Will this help, I am getting a P0492 code (Secondary air sytem - bank 2)?

Seafoam has never hurt my O2 sensors. Filling the tube with Seafoam as above will clear the secondary air passages and in my case corrected the low secondary air flow code.
Listen for the secondary air pump hum at start up and inspect the hose. If it doesn't fill up after you've poured 1 1/2 oz of Seafoam there might be a leak in the hose.

I did have a hole in the secondary pump hose to valve about six months ago. It threw a CEL and I replaced the hose. Now I keep getting CEL for this and bank2 low flow indicated. (I am using a peake reader for codes)

I will give the seafoam a try.
About how long does it take for the smoke to burn off?

I have also noticed the pump sounds like a mini turbine engine (high pitch whine) when it is running lately, is this from the low flow or is the pump going bad?

I have also noticed the pump sounds like a mini turbine engine (high pitch whine) when it is running lately, is this from the low flow or is the pump going bad?

The pump whines for about 2 minutes at start. If there is back pressure the pump would meet resistance and would be louder. The pump is like a leaf blower so the fact it turns on and powers off after 2 minutes means the system is working mechanically. Build up of carbon will cause a code if the O2 sensor is not measuring enough flow about 2 minutes after start up.

Mine had the P1421 and P1423 codes and it was a leak in the air pump vaccuum line right below cylinder #3. I repaired the plastic vaccum line with rubber vaccuum hose, cleared the codes and they didn't come back.

Mine had the P1421 and P1423 codes and it was a leak in the air pump vaccuum line right below cylinder #3. I repaired the plastic vaccum line with rubber vaccuum hose, cleared the codes and they didn't come back.